Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
Q: I'm talking about an incurable disease which is a lifelong affliction but is not fatal. Usage - She is suffering from a ____________ illness. I can't use terminal here because terminal means 'predicted to lead to death, especially slowly; incurable.'.
A: 
chronic From the Oxford English Dictionary (OED) Of diseases, etc.: Lasting a long time, long-continued, lingering, inveterate; opposed to acute OED cites as an example: 1994 Jrnl. Internal Med. 236 685 A 23-year-old female student exhibited all the characteristics of chronic factitious disorder with physical symptoms (Munchhausen's syndrome): deliberate simulation of illness, peregrination, fantastic pseudology and dramatic circumstances on admittance. (Emphasis added) OED contrasts chronic with acute acute: Of a disease, symptom, etc.: coming quickly to a crisis or conclusion; of rapid onset and short duration; of recent or sudden onset; contrasted with chronic The Cambridge English Dictionary gives as examples (rearranged): chronic arthritis/pain She suffers from chronic pain in her knees. I have a chronic bowel disease